I've had cowl hoods on several trucks in the past and I just chunked the underhood liner and painted the underside of the hood to match.
2014 Ram 1500 Express 'Black Edition' SCSB 2wd - 5.7 Hemi
Mufflex Performance DOD14M Exhaust, Wheatley Performance Tune, Vararam Air Grabber Intake, Moe's Performance ported 87 mm TB, 180 degree stat
2013 Sierra 1500 ECSB. SOLD
2012 Silverado 1500 ECSB 2wd Z71 - Black 5.3L - SOLD
2007 Silverado RCSB NNBS--Greystone Metallic 4.8L-3.73 - SOLD